US2422634A - Microhardness testing instrument - Google Patents

Description

June 17, 1947' H. Ril-:PERT ET AL` MICRO HARDNESS TESTING INSTRUMENT Filed March l0, 1959 llllllllllw 13 `unh .3

=vll////////// v, 4 W Y ,d-WM

Patented June 17, 1947 2,422,634 v MICROHARDNESS TESTING INSTRUMENT Hermann Riepert and Heinrich Broschke, Wetzlar, Germany; vested in the Attorney General of the United States Application March 10, 1939, Serial No. 260,905

In Germany April 26, 1938 Sections 3 and 14, Public Patent expires 1 Claim.

This invention relates to improvements in portable hardness testinginstruments. The object of the invention is tov provide a relatively small compact testing mechanism vwhich shall be especially well adapted to be used in combination with a microscope as an integral part thereof. The testing mechanism is characterized, among other features, by the fact that the testing or penetrating member is so supported that it opcrates under its own weight during the testing operation.

Some prior hardness testing devices or ma; chines operate with two weights. When the testing member contacts the object a rst smaller weight is placed upon or caused to operate upon the testing member to effect a first penetration into the object. Thereafter a heavier weight is used for the same purpose. The difference in penetration is then measured by suitable well known means.

Devices which operate inthis manner must be constructed very substantially. They are relatively heavy and expensive. They cannot be used for testing heavy or immovable objects because the testing device itself is not portable as this term is understood. It has therefore been proposed to use smaller hardness testingdevices ofthe portable type. With such a device the operation is carried out by placing the device upon the object and the weight of the entire device itself is utilized as a first weight to cause penetration of the object. Thereafter a weight is causedto fall upon the penetrating member in order to obtain a second deeper penetration. The difference in penetration is measured by well known means. The German Patent 572,671, March 20, 1933 refers to these types of devices.

Other devices are spring actuated and suffer from inexactness due to uneven uncontrollable tension of the spring. Still other devices utilize weights placed upon levers or arms, and it has been found that they are not sufiiciently accurate.

In the present invention` the hardness testing instrument or device is constructed so as to be incorporated in a microscope and carried about and used as conveniently as such instruments are customarily used. The penetrating testing element is supported in such a manner that when the microscope is placed upon an object to be tested, the testing element automatically comes to rest upon the object under its own weight. The engagement of the testing element with the object is utilized to open an electric circuit with means to signal that the element is supported by gravity and that the operation may l begin.

Law 690, August 8, 1946. April 26, 1958 Y Thereafter the penetrating of the object is done by the testing element under its own weight.

Should it happen that the testing element by contacting the object is raised too high so as not to be able to function under its own weight, the circuit is again closed and signals this condition. An additional hand weight member may be provided to increase momentarily the weight of the testing element. The invention is illustrated in the accompanying drawing which is a general view of the instrument with parts broken away and parts in section. Only so much of the microscope is shown as is necessary for understanding the invention.

in the drawing the microscope is identified by the usual microscope tube l. To the bottom thereof` there is secured a bracket 25 having a central'bore 32 in alinement with the microscope tube I.V The bracket 25 also supports ball bearing means 34 for the support of a sliding member 2 which supports the microscope objective 3 and the hardness testing device 4. Preferably the arrangement is such that either the objective or the testing device may be moved in under the microscope tube. In the one case to conveniently support the testing device centrallyof the apparatus as shown, in the other case to align the tube and the objective. It is not necessary for practising the invention that this particular arrangement be used. It will be observed however that by combining the hardness testing device with the microscope it is an easy matter to observe the results of the testing by means of the microscope by merely sliding the objective in under the tube. It will also be clear that inasmuch as the tube is adjusted in the usual manner in microscopes it is not possible to use falling weights or like means upon the testing device, nor weights to such an extent as will disturb the tube adjustment.

Referring to the drawing the testing device comprises the general casing 4 which is supported in the slide 2. The casing supports a plate i6 which is insulated as at 9. The plate supports the testing element 1 which is in the form of a vertical shaft. Above the plate I6 this shaft carries a contact disk I4. Below the plate the shaft carries another contact disk I3. The distance between the disks is somewhat greater than the thickness of the plate I6. The testing element carries at its lower end a suitable testing penetrating point 6 and above the latter the testing element is enlarged to form a weight 8. The testing element is guided vertically by two thin lamellae Il and I2. These are of sufficient strength to guide the element 'I against tipping provide supporting means for the testing element but they are not strong enough to interfere with so arranged that the operator may observe the the free vertical movement of the element. An element directly. Such an alternative embodiadditional loose weight4 I9 is provided to rest upon ment is not shown.

the weights when necessary. The weight I9 may 5 We claim:

be lifted orf the weight 8 by a ring 20 provided In a microhardness testing instrument as dewith a handle 2l accessible from the outside of Y scribed, a microscope having a microscope tube, the casing 4. an objective and a testing device including a The plate I 5 is connected by a wire I5 to a testing element, a bracket upon the lower end of source of electric current 28and'a'1amp I8. The 10 said tubev having a centrally extending vertical return wire of the circuit may begrounded as bore in 'alinement with said tube, horizontally at I'l. The numeral 5 indicates the object 30 is disposedV guiding means in said bracket at the a switch. f bottom of` and intersecting said bore, a slidable When the operator intends to use the instrumember supported in said guiding means, means ment he moves the member in its supporting l5 for supporting said testing device and said ob- A`upon the object 5. The lcircuit remains closed 20 supporting means including means for supportcircuit is broken at I4-I5, the lamp goes out and ing brought into Contact under its own Weight thus signals the beginning of the testing opera- 2'5 with an object .to be tested and which said ele- 4tion. 'Should the circumstances be such that the ment automatically reassumes upon removal from element 7 islifted too high, then the circuit is the object, means for increasing the weight of thssignalsto the operatorto adjust the1nstruv30 by said 'element to indicate its respective said has been placed upon the object, the circuit will y HERMANN RIEPERT.

be broken as aforesaid and now the testing ele- Y Y Y HEINRICH BROSCHKE. ment 'I will rest upon the object under its own s s weight to cause the necessary penetration of the 35 REFERENCES CITED Pb'ht -5- .H110 addtna'l Weight is necessary the The following references are of record in the `ottitator lifts thetgight i9 of 'the weight t, and me 0, this patent:

under the microscope tube `for examination of UNITED STATES PATENTS thepenetration point or area of 'the object. 40 Number Name Date .From the `1orgoingy it will be noted that the '1,335,972 Wson Nw 1J 1932 testine elefrleht'isf''mally Supportedby gravity 1,478,621 smith et al. Dec. 25, 1923 anais automatically lifted out O'fsifts sup- 2,-13s,411 Tomebohm N0v29, 193s po'rted'position andbrought to rest by gravity 1 1,512,192 Benko Oct. 21, 1924 `tiroir'the object eithrjunder its own normal 45 1,985,916 Coates et a1. Jan. 1, 1935 weight ,or withth'elod'se Weight added. The elec- 1,452,910 Moore et ai Apr. 24, 1923 tric signal meansseve to notify the Operator 2,003,910 Stephenson June 4, 1935 ,thatthe testine element is in proper 'Operative 1,875,134- P'nund Aug. 30, 1932 .position for the test. The device is small, corn- 50 '1,346,943 Desautefls Feb, 23J 1932 pact, easily portableand conveniently incorpo- Y rated. mts the microscope structure. FOREGN PATENTS y It will further be clear that vthe operation of Number Country Date the testing element or the position thereof need 467,806 Great Britain June 23, 1937 not necessarily 'be signalled in the manner dis- 464,005 Great Britain 'Apn 9, 1937 closed. T t is'within the scopeof the invention to 55 v195,094 Germany Feb. 6, 1908

Images